Fluoxetine

Fluoxetine

[20mg tablets 5 cents]

ADMINISTRATION ROUTES:

  • PO

ALTERNATIVE NAMES:

  • Fluox, Prozac

ICU INDICATIONS:

  1. AntidepressantNote: it is rare for antidepressants to be commenced in patients in the ICU. Most ICU patients have ‘situational depression’ and the risks of medication often outweigh the benefits. (see WARNINGS)

PRESENTATION AND ADMINISTRATION:

  • PO:
    Capsules:

    Fluox 20mg capsules (purple / light green), Prosac 20mg capsules (green / cream)
    Dispersible Tablets:
    Fluox dispersible 20mg tablets (white)

DOSAGE:

  • PO:
    20mg-60mg daily

DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:

  • Dose in renal impairment [GFR (ml/min)]
    <10: dose as in normal renal function or on alternate days
    10-20: dose as in normal renal function or on alternate days
    >20-50: dose as in normal renal function
  • Dose in renal replacement therapy
    CAPD: dose as in normal renal function or on alternate days
    HD: dose as in normal renal function or on alternate days
    CVVHDF: dose as in normal renal function or on alternate days

DOSAGE IN PAEDIATRICS:

  • PO:
    0.5mg/kg (max 20mg) daily, increase to maximum of 1mg/kg (max 40mg) 12 hourly

CLINICAL PHARMACOLOGY:

  • Fluoxetine is a serotonin specific reuptake inhibitor antidepressant

CONTRAINDICATIONS:

  1. hypersensitivity to fluoxetine or other SSRIs

WARNINGS

  • Use in Patients With Concomitant Illness
    Clinical experience with Prozac in patients with concomitant systemic illness is limited. Caution is advisable in using Prozac in patients with diseases or conditions that could affect metabolism or hemodynamic responses.
  • Suicidality
    Patients with major depressive disorder (MDD), both adult and paediatric, may experience worsening of their depression and/or the emergence of suicidal ideation and behaviour (suicidality) or unusual changes in behaviour, whether or not they are taking antidepressant medications, and this risk may persist until significant remission occurs.
  • Hyponatremia
    Cases of hyponatremia (some with serum sodium lower than 110 mmol/L) have been reported. The hyponatremia appeared to be reversible when Prozac was discontinued. Although these cases were complex with varying possible aetiologies, some were possibly due to the syndrome of inappropriate antidiuretic hormone secretion (SIADH).

PRECAUTIONS

  • General:
    Anaphylactoid events, including bronchospasm, angioedema, laryngospasm, and urticaria alone and in combination, have been reported. Pulmonary events, including inflammatory processes of varying histopathology and/or fibrosis, have been reported rarely. These events have occurred with dyspnea as the only preceding symptom.
    Published case reports have documented the occurrence of bleeding episodes in patients treated with psychotropic drugs that interfere with serotonin reuptake. Subsequent epidemiological studies, both of the case-control and cohort design, have demonstrated an association between use of psychotropic drugs that interfere with serotonin reuptake and the occurrence of upper gastrointestinal bleeding.
  • Laboratory Tests:
    No tests in addition to routine ICU tests are required.
  • Drug/Laboratory Test Interactions:
    None noted.

IMPORTANT DRUG INTERACTIONS FOR THE ICU

  • The combination of Tramadol and SSRIs should be used with caution due to the increased risk of serotonin syndrome with concomitant use. Patients on stable doses of phenytoin and carbamazepine have developed elevated plasma anticonvulsant concentrations and clinical anticonvulsant toxicity following initiation of concomitant fluoxetine treatment.

ADVERSE REACTIONS

  • Body as a Whole:
    Flu syndrome
  • Cardiovascular System:
    Vasodilatation
  • Digestive System:
    Nausea, diarrhoea, anorexia, dry mouth, dyspepsia
  • Nervous System:
    Insomnia, anxiety, nervousness, somnolence, tremor
  • Respiratory System:
    Pharyngitis, sinusitis
  • Skin and Appendages:
    Sweating, rash

Critical Care Drug Manual

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